Picodeck

Firmware using tinyusb to turn a Raspberry Pi Pico into a device that works with Elgato's Stream Deck software.

Flashing

1. Grab the latest uf2 from the releases page, here
2. Press the BOOTSEL button and hold it while you connect the other end of the micro USB cable to your computer.
3. Drag the uf2 to the pico flash drive that shows up
4. Wait for it to reboot
5. Done!

Wiring

Switches

Pins 2,3 switch 1
Pins 7,8 switch 2
Pins 12,13 switch 3

Neopixel (optional, shows the led color in settings)

Pin 34 neopixel data
Pin 40 neopixel power
Pin 38 neopixel ground

I used the ring here: https://www.adafruit.com/product/1643

Enclosure options

It should be trivial to wire this up to exisiting foot pedal hardware or arcade buttons.

I went a little overboard and built the foot switch that Adafruit shared:

https://learn.adafruit.com/three-button-foot-switch

Pico mount here: https://github.com/DDRBoxman/picodeck/blob/main/enclosures/pedal/pi-pico-holder.stl

Development

Building on macOS

brew tap ArmMbed/homebrew-formulae
brew install arm-none-eabi-gcc
mkdir build
cd build
cmake ..

Protocol

The protocol mostly matches the existing Stream Deck devices but with a few tweaks for the pedal.

Debugger breakpoints on the RP2040 and wireshark with a real Stream Deck pedal were very helpful at figuring out how the Stream Deck software talks to the devices.

Startup

When the software starts up it asks the device for a software version number and then a serial string, as long as both of these respond the device shows up in the Stream Deck software.

Stream Deck Pedal

The pedal has a new command on the output endpoint to set the led color:

02 0b FF FF FF
       R  G  B

The input endpoint report for the pedal is shorter than the proper stream decks:

01 00 03 00 00 00 00 00
   button:   1  2  3

Tools

https://github.com/todbot/mac-hid-dump

https://eleccelerator.com/usbdescreqparser/

https://github.com/todbot/hidpytoy

https://www.wireshark.org

Resources

https://github.com/mdonoughe/streamdeck-rs

https://github.com/RudolfVonKrugstein/streamdeck-hid-rs

https://github.com/ryankurte/rust-streamdeck

https://den.dev/blog/reverse-engineering-stream-deck/

https://gist.github.com/cliffrowley/d18a9c4569537b195f2b1eb6c68469e0